The present invention concerns a rim intended to be equipped with a tire, more particularly of the tubeless type.
French Patent 2 257 442 teaches that such rims are generally provided with a groove which serves for the mounting and removal of the tubeless tire. As this rim groove serves only temporarily and its presence is disturbing, it has been proposed that it be shifted in the direction of the outer rim flange and that it be closed by means of a removable device. In order to assure perfect tightness of the pneumatic cavity and permit easy positioning, locking in position and removal, that patent recommends the use of a flexible, stretchable annular packing which forms the seat for the bead of the tire in question and, preferably, the use of a rubber packing which is compressible without variation of volume.
As shown in FIG. 6 of that patent, without other comment, the annular packing can have an inflation valve.
Whether it be under a tensile force, as is the case during the mounting and the putting in place of the packing, or as partially the case under the effect of centrifugal force, or under a compressive force under the effect of the clamping of the bead on the packing, the metal or plastic valve introduces a local variation of properties into the packing and accordingly a variation in behavior of the bead which rests on said packing. Conversely, the area around the valve is subjected to concentrations of stresses, which favors a premature detachment of the valve from the rubber of the packing. Furthermore, although less so than in the event that it is threaded into a metal part, the valve nevertheless remains vulnerable to impacts, particularly at the place of its embedment.